The present invention generally relates to an improved locking device for a door lock in a motor vehicle, and more particularly to a locking device which prevents the unauthorized unlocking of a door from the inside.
Locking devices for the door lock of a motor vehicle are known such as disclosed by German Offenlegungsschrift 3,500,550. This specification suggests the possible isolation of an inner handle from the door lock by a coupling which can be remotely controlled as well as mechanically actuated. However, in this arrangement, the isolating coupling is required to be the same isolating coupling which also isolates the outer handle from the door lock when the locking position is selected. Further, the locking position can always be selected and cancelled by an inner security element irrespective of whether the door lock has been locked from the inside, from the outside or by remote control (central locking). Furthermore, the locking position can even be cancelled simply by actuating the inner handle in the process of opening the door from the inside.
Door locks are also known (German Auslegeschrift 2,000,944, German Auslegeschrift 2,522,301), in which both the outer and inner handles are always free-moving, irrespective of whether the vehicle has been locked from outside or from inside, that is to say uncoupled from the door lock. However, the inner security element is blocked with locking from the outside, but with locking from the inside, the inner security element can also cancel again the locking position selected by the inner security element.
In the above-mentioned arrangement, it is not possible to have an inner security element which is countersunk in a locking position and which cannot be grasped by hand. Thus, two actions always have to be performed in order to open even a door locked from the inside.
Additionally, there is already a known combined central-locking and theft-prevention system (German Patent Specification 3,307,542), in which unauthorized opening of any door after the selection of the locking position from outside is prevented by an additional detent pawl brought into engagement with a rotary door-lock latch in a power-operated way.
Furthermore, it is known (German Offenlegungschriften 2,709,157 and 2,709,158) to prevent the release of a door lock by an inner security element, employing a detent for preventing further movement, after an idle stroke of the inner security element. However, these components can exert their effect reliably only when there is continuous activation of associated vacuum-type control elements.
Moreover, in a combined central-locking and break-in/theft alarm system, (German Patent Specification 3,516,732) the control of the break-in/theft alarm system is controlled in a similar manner as the control of the central-locking system, by the same potential-change switch when there is a simultaneous key-recognition signal from a lock-cylinder switch.
An object of the invention is to provide a locking device that is better protected against unauthorized opening from inside, such as to prevent unauthorized opening by a child or after a break-in.
According to the invention, this object is achieved by providing a locking device for a door lock in a motor vehicle having a locking position and a release position selectable from a central location, even by remote actuation, comprising security elements for selecting the locking position of the door lock including a inner security element for manually selecting the locking position of the door lock and at least one outer handle selectively uncoupled from the door lock by an isolating coupling actuated by the security elements. Also included is a connecting arrangement for actuating the isolating coupling to at least assume an uncoupling state upon manual selection of the locking position by the inner security element and an inner handle disengageably coupled to the door lock and adapted to cancel the locking position in the process of opening a particular door when the locking position has been selected manually by the inner security element. A first disengageable coupling is provided for disengageably connecting the inner handle to the door lock, the first disengageable coupling being disengageable during the selection of the locking position from the outside of the vehicle, only indirectly by a first actuating drive. Further, the connecting arrangement, between the inner security element and the isolating coupling, is uncoupleable at least in a lock releasing direction of actuation of the inner security element.
It is presupposed, in accordance with certain preferred embodiments of the present invention, that the "selection of the locking position from outside" can be triggered remotely, for example, by a security element or control element of a central-locking system, under the control of, for example, a lock cylinder on another door.
In accordance with certain advantageous features of preferred embodiments of the present invention, the locking device provides expedient possibilities of use on door locks with outer security elements and/or a child-proof facility. Child-proof facility, as used herein, refers to being able to secure a door against careless opening from inside, but at the same time not having to lock this door against opening from outside.
The locking device according to the invention also provides two different options for preventing unauthorized use of the inner security element in the releasing direction of actuation.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.